The present invention provides a system for latching, closing, and locking drawers in a cabinet.
Hospitals and other health care facilities often use wheeled cabinets for storing medications and other supplies, and for transporting such medications and supplies from one patient to another. These cabinets generally have numerous drawers, in which many different types of medications may be kept separate within the cabinet. Some of the medications are expensive, and some may be controlled substances, such as narcotics. Thus, the security of the cabinet is important, and various governmental regulations, as well as rules of the particular institution, require that all drawers of such cabinets be locked when the cabinet is unattended.
The prior art contains many examples of cabinets having manual or automatic means for locking drawers. One problem with these prior art cabinets is that it is possible to leave one or more drawers slightly ajar, just beyond the reach of the latching or locking means. If one locks such a cabinet, the drawers which are slightly ajar will remain unintentionally unlocked. Because the unlocked drawers were nearly closed, it would not be visually apparent that one or more drawers had just missed the latch.
Regardless of where a fixed latch is positioned, there is always some drawer position in which the drawer will just miss being latched, and will still look almost the same as another drawer that has been caught by the latch. This ambiguity can result in unattended cabinets in which drawers remain unintentionally unlocked.
The present invention solves the above-described problem, by providing a latch mechanism which pulls each drawer fully closed as part of the latch and lock cycle. The invention is especially useful in medical applications, as described above, but can be used in any other field in which it is necessary to keep one or more drawers locked.
The present invention comprises a system for latching, closing, locking, and unlocking a drawer, the system being suitable for use in medication transport carts, or with other cabinets of drawers which must be closed and locked after use. The drawers may be arrayed in rows, columns, or both. The present invention includes 1) a drawer latch mechanism with latch fingers which capture the drawers, and which pull the drawers closed if necessary, retaining the drawers such that they cannot be subsequently pulled open until purposely unlatched, and 2) a lock mechanism which provides the motive power for the latching and closing operation, and which provides the means for locking the mechanism so that the drawers remain closed, and which enables mechanical or electromechanical unlocking of the drawers. In the preferred embodiment, the two mechanisms are connected by a cable and pulley system.
The drawer latch mechanism of the present invention includes a plurality of latch fingers, at least one latch finger for each drawer. It also includes a plurality of crankshafts, one for each row of drawers. Each crankshaft has an offset or eccentric crank portion corresponding to each column of drawers. These eccentric crank portions engage the latch fingers to move them in and out and up and down. The crankshafts are synchronously connected by a pair of drive links such that they move in unison. The crankshafts are driven by the interconnecting cable from the lock mechanism, described below. As the crankshafts rotate, the latch fingers first drop down to engage catches on the rear portions of the drawers. Then, as the crankshafts continue to rotate, the latch fingers retract to pull closed any drawers whose catches they have engaged. When the fingers are fully retracted, the drawers are fully closed, and the crankshaft is positioned such that the forces on the latch finger do not significantly tend to rotate the crankshaft. The latter is often called the top-dead-center position.
In addition to latching and pulling the drawers shut, the rotation of the crankshafts also winds a torsion spring. This spring serves to return the latch fingers to their extended and raised (unlatched) position when tension on the interconnecting cable is relaxed.
The lock mechanism provides the motion and force to operate the drawer latch mechanism through the interconnecting cable, and includes means to latch itself in the locked position. This internal latch is released by the operator to unlock the drawers when desired. The motive power for the lock mechanism may be manual or electromechanical. In the manual implementation, the operator moves a handle to close and lock the drawers, and uses a key to unlock and unlatch them. In the electromechanical implementation, a motor is added which may be used to pull the drawers closed until the internal mechanical latch engages. The motor then returns to its home position. To unlock and unlatch the drawers, the operator may either use a key or may cause the motor to perform the unlocking function. If used, the motor momentarily moves in reverse, far enough to disengage the internal latch in the lock mechanism. Once the lock mechanism is unlatched, the interconnecting cable tension is relaxed, allowing a return spring on the drawer latch mechanism to unlatch the drawers and to return the lock mechanism to its unlocked position. Following either manual or electromechanical unlocking, the drawers are opened manually.
The present invention therefore has the primary object of providing a system for closing and locking a drawer.
The invention has the further object of providing a system for closing and locking a plurality of drawers simultaneously, such as the drawers of a cabinet or the like.
The invention has the further object of closing and locking a drawer that has been left some distance ajar.
The invention has the further object of closing and latching all of the drawers of a cabinet which are initially spaced a predetermined distance from a fully closed position.
The invention has the further object of making it visually apparent, to an operator, which drawer of a multiple-drawer cabinet has been left sufficiently ajar to avoid being locked.
The invention has the further object of providing means for locking and unlocking a drawer, both of which may be manually or electromechanically operated.
The invention has the further object of enhancing the security of medications stored in health care facilities.
The reader skilled in the art will recognize other objects and advantages of the present invention, from a reading of the following brief description of the drawings, the detailed description of the invention, and the appended claims.